Product manual

Glossary
77 A1 69UP Rev00 G-5
Index Point
The reference point on a disk surface that determines the start of a track.
IOCP
Input/Output Configuration Program.
I/O Device
An addressable input/output unit, such as a disk device.
IPL
Initial Program Loading.
K
Kilobyte (K)
1024 bytes.
L
Least Recently Used Algorithm (LRU)
The algorithm used to identify and make available the cache space by removing the least recently
used data.
Logical Unit
A physical or virtual device addressable through a target. A physical device can have more than
one logical unit.
Logical Unit Number (LUN)
An encoded three-bit identifier for the logical unit.
Logical Volume
A user-defined storage device. In the Symmetrix subsystem, the user can define a physical disk
device as one to eight logical volumes.
Logical Volume Manager (LVM)
The part of the AIX system responsible for disk subsystems. Interaction with the LBM is done via
SMIT menus or via stand-alone commands.
Long Miss
Requested data is not in cache and is not in the process of being fetched.
Longitude Redundancy Code (LRC)
Exclusive OR (XOR) of the accumulated bytes in the data record.